akinesis

Akinesis, from Greek a- “without” and kinesis “movement,” is a clinical term that denotes the absence or marked reduction of voluntary movement. In medical usage it is related to, but distinct from, akinesia (difficulty initiating movement) and hypokinesia (reduced movement amplitude). Akinesis can be a symptom of disorders affecting the motor system, particularly the basal ganglia and related circuits that regulate voluntary motion.

Common causes include movement disorders such as Parkinson’s disease and other forms of parkinsonism, cerebrovascular disease, traumatic brain injury, brain tumors, infections, and metabolic or drug-induced states. The underlying mechanism often involves dysfunction of dopaminergic pathways or disruption of motor circuits in the frontal cortex and basal ganglia.

Clinical presentation ranges from a general reduction in spontaneous movement to an inability to initiate actions. Patients may exhibit hypokinesia, diminished facial expression, reduced arm swing during gait, and slowed or absent voluntary movements. In severe cases, akinesis can contribute to akinetic mutism, a state of wakefulness with little or no voluntary speech or movement.

Diagnosis is primarily clinical, supported by neurological examination and neuroimaging to identify underlying etiologies. Treatment targets the underlying cause: dopaminergic medications for parkinsonism, management of stroke or brain injury, and addressing drug-induced states. Rehabilitation with physical and occupational therapy can help preserve mobility and function, while prognosis depends on the condition’s nature and response to therapy.